Chainline and pedal alignment for old Cannondale

My old Cannondale AA series bike needed a new drivetrain (rings,
cogs, chain and maybe derailers). There's nothing discernibly
wrong with the frame and other components, so it's worth fixing.

For the moment, I've installed some cheap rings, chain and cogs
supplied by an LBS, but the quality of the parts and the way they
fit make me yearn for parts that fit together somewhat better.

The most obvious sticking point is the bottom bracket: The new
chainrings/crank had the wrong offset until I turned the crank
spindle over and shimmed the fixed cup. Now it all works, but
the pedals are shifted a good half inch to the left and there's
only about one thread engaged on the lock ring..

The bottom bracket is British thread, anything that fits would
be of interest.

How do folks get chainlines and pedals to line up? A couple
millimeters in the seat make a noticeable difference, so I
suspect I'll care about getting the pedals correct left to right.
If it's unlikely to be true a warning would be appreciated.

Thanks for reading,

bob prohaska

On Mon, 25 Nov 2013 03:17:43 +0000 (UTC), User Bp
wrote:

My old Cannondale AA series bike needed a new drivetrain (rings,
cogs, chain and maybe derailers). There's nothing discernibly
wrong with the frame and other components, so it's worth fixing.

For the moment, I've installed some cheap rings, chain and cogs
supplied by an LBS, but the quality of the parts and the way they
fit make me yearn for parts that fit together somewhat better.

The most obvious sticking point is the bottom bracket: The new
chainrings/crank had the wrong offset until I turned the crank
spindle over and shimmed the fixed cup. Now it all works, but
the pedals are shifted a good half inch to the left and there's
only about one thread engaged on the lock ring..

The bottom bracket is British thread, anything that fits would
be of interest.

How do folks get chainlines and pedals to line up? A couple
millimeters in the seat make a noticeable difference, so I
suspect I'll care about getting the pedals correct left to right.
If it's unlikely to be true a warning would be appreciated.

Thanks for reading,

bob prohaska

The thing about chain lines for a rear derailer bike is that no matter
how accurately you align things it immediately goes out of line as
soon as you shift :-)

You don't say what type of bottom bracket you have but it is one of
those one piece things, see
http://www.amazon.com/Shimano-UN54-B.../dp/B0039369B4
they come in different length axles to help align things.
See http://sheldonbrown.com/bbsize.html for more details.
--
Cheers,

John B.

On 11/24/2013 9:17 PM, User Bp wrote:
My old Cannondale AA series bike needed a new drivetrain (rings,
cogs, chain and maybe derailers). There's nothing discernibly
wrong with the frame and other components, so it's worth fixing.

For the moment, I've installed some cheap rings, chain and cogs
supplied by an LBS, but the quality of the parts and the way they
fit make me yearn for parts that fit together somewhat better.

The most obvious sticking point is the bottom bracket: The new
chainrings/crank had the wrong offset until I turned the crank
spindle over and shimmed the fixed cup. Now it all works, but
the pedals are shifted a good half inch to the left and there's
only about one thread engaged on the lock ring..

The bottom bracket is British thread, anything that fits would
be of interest.

How do folks get chainlines and pedals to line up? A couple
millimeters in the seat make a noticeable difference, so I
suspect I'll care about getting the pedals correct left to right.
If it's unlikely to be true a warning would be appreciated.

Thanks for reading,

bob prohaska


In the same way that a spark plug which ran well in your 283
hits the piston when you drop it into a Toyota, there is a
correct application for whatever crank you are using.
There are often reasonable substitutes and then there are
completely incompatible parts ( probably most random
selections).

Spindle matches crank, cup thread matches frame. You matched
the BSC threading but what crank are you using?

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

ima crank ima crank ima crank

http://s3.amazonaws.com/rapgenius/fi..._trash_can.jpg

what you need izza lawyer for a new frame !

we have one...search for Jay Beattie

Jay is a famous west coast lawyer and rep fpr Cdale

LBS LBS ? cheap ? you asked for cheap ? cheap cheap cheap ?

try the internet not the LBS...

itsa PART A uses Parts vb,jk, 78ty, and 64try

https://www.google.com/#q=cannondale...+rebuild+parts

I have tried cheap from mailorder getting absolute crap as a joke for buying chea...like chainrings without teeth.

AMuzi wrote:

Spindle matches crank, cup thread matches frame. You matched
the BSC threading but what crank are you using?

I believe I'm looking for a new crank. The old setup used a square
taper SR Apex on the drive side with two half-step chainrings and a
granny. The non-drive side had a Suntour arm. Just for fun, the caps
on the spindle bolts say Sugino 8-) Cups are Shimano 1.37/24 with
British threading (left-hand on the right, right hand on the left).
The spindle is marked 3RB Cr-Mo 83-K.

I'm told rings for the SR are scarce and expensive, the spindle and
cups are scored and eventually should be replaced. It looks as if the
best course is to replace the bottom bracket and everything connected
to it. The temporary crank is a steel-ringed Shimano which will keep
the bike usable while I look for better parts.

The one feature I'd like to retain is having a granny gear. From time
to time I pull a heavy cargo trailer. Otherwise the bike is used for
exercise and grocery chasing, so optimization for performance isn't
a huge issue. Mostly I don't want to butcher a good bike that has
worked well for over twenty years.

Thanks for reading,

bob prohaska
..

Bob: What you need is a bottom bracket with an axle long enough to give you the correct chain line. The correct chain line is determined by the width of the hub/cluster on the back wheel. The correct axle width in the bottom bracket to give you that chain line is determined by the design of the crank. So you have to obtain two numbers. What is the best chain line for the cluster, and what is the chain line with some nominal bottom bracket axle length on your particular cranks, a number which you can then use to calculate (apply here again, because it isn't obvious how you do it) the required bottom bracket axle length. -- Andre Jute

On Monday, November 25, 2013 3:17:43 AM UTC, User Bp wrote:
My old Cannondale AA series bike needed a new drivetrain (rings,

cogs, chain and maybe derailers). There's nothing discernibly

wrong with the frame and other components, so it's worth fixing.



For the moment, I've installed some cheap rings, chain and cogs

supplied by an LBS, but the quality of the parts and the way they

fit make me yearn for parts that fit together somewhat better.



The most obvious sticking point is the bottom bracket: The new

chainrings/crank had the wrong offset until I turned the crank

spindle over and shimmed the fixed cup. Now it all works, but

the pedals are shifted a good half inch to the left and there's

only about one thread engaged on the lock ring..



The bottom bracket is British thread, anything that fits would

be of interest.



How do folks get chainlines and pedals to line up? A couple

millimeters in the seat make a noticeable difference, so I

suspect I'll care about getting the pedals correct left to right.

If it's unlikely to be true a warning would be appreciated.



Thanks for reading,



bob prohaska

Andre Jute wrote:
Bob: What you need is a bottom bracket with an axle long enough to give you the correct chain line. The correct chain line is determined by the width of the hub/cluster on the back wheel. The correct axle width in the bottom bracket to give you that chain line is determined by the design of the crank. So you have to obtain two numbers. What is the best chain line for the cluster, and what is the chain line with some nominal bottom bracket axle length on your particular cranks, a number which you can then use to calculate (apply here again, because it isn't obvious how you do it) the required bottom bracket axle length. -- Andre Jute

What are the standard reference surfaces on the crank and spindle?
One can measure things like the face of the fixed cup, the end of
the spindle and the edge or centerline of the chainrings. It's hard
to estimate how far the spindle will enter the crank. If there's a
rule of thumb that says the inner face of the crank boss is always
"X" millimeters from the end of the crank spindle that would be a
huge help. Better yet if there's a "Y" from bottom bracket to inner
chainring. I've not seen anything of the kind published.

Thanks for reading,

bob prohaska

On Monday, November 25, 2013 3:17:43 AM UTC, User Bp wrote:
My old Cannondale AA series bike needed a new drivetrain (rings,

cogs, chain and maybe derailers). There's nothing discernibly

wrong with the frame and other components, so it's worth fixing.



For the moment, I've installed some cheap rings, chain and cogs

supplied by an LBS, but the quality of the parts and the way they

fit make me yearn for parts that fit together somewhat better.



The most obvious sticking point is the bottom bracket: The new

chainrings/crank had the wrong offset until I turned the crank

spindle over and shimmed the fixed cup. Now it all works, but

the pedals are shifted a good half inch to the left and there's

only about one thread engaged on the lock ring..



The bottom bracket is British thread, anything that fits would

be of interest.



How do folks get chainlines and pedals to line up? A couple

millimeters in the seat make a noticeable difference, so I

suspect I'll care about getting the pedals correct left to right.

If it's unlikely to be true a warning would be appreciated.



Thanks for reading,



bob prohaska

On 26/11/13 14:58, User Bp wrote:

What are the standard reference surfaces on the crank and spindle?
One can measure things like the face of the fixed cup, the end of
the spindle and the edge or centerline of the chainrings. It's hard
to estimate how far the spindle will enter the crank. If there's a
rule of thumb that says the inner face of the crank boss is always
"X" millimeters from the end of the crank spindle that would be a
huge help. Better yet if there's a "Y" from bottom bracket to inner
chainring. I've not seen anything of the kind published.

Thanks for reading,

http://sheldonbrown.com/bbsize.html

There is much to learn from Mr Brown.

--
JS

On another site is a mathematical explanation with photos ( one how-not-to mislabeled) of how I determined the correct bottom bracket axle width for my Sugino Cospea cranks to a 54mm Rohloff chainline. See message 6 for the reference planes I used. http://www.thorncycles.co.uk/forums/...19603#msg19603

Andre Jute